Field of the Invention
The present invention relates to a carbon member having a multilayer structure in which a carbon resin composition material layer and a porous carbon material layer are integrated into a single body, and a manufacturing method for the carbon member, and relates particularly to a carbon member that is suitable as a battery member for use in a battery such as a redox flow battery or a fuel cell, and a manufacturing method for the carbon member. Priority is claimed on Japanese Patent Application No. 2013-082949, filed Apr. 11, 2013, the content of which is incorporated herein by reference.
Description of Related Art
Conventionally, sintered carbon obtained by conducting sintering in a high-temperature process has been widely used as the material for carbon members used as battery members such as electrodes. By using sintered carbon, a high-performance carbon member having low electrical resistance and excellent heat resistance and corrosion resistance can be obtained.
However, carbon members formed from sintered carbon suffer from a number of problems, including being prone to cracking, having unsatisfactory flexural strength, and being difficult to handle. Accordingly, when batteries are manufactured using a carbon member formed from sintered carbon, the workability and processability are inadequate, and satisfactory productivity cannot be achieved.
As a result, in recent years, carbon resin composite materials formed from carbon and resins are increasingly being used as the materials for carbon members. Carbon members formed from carbon resin composite materials can easily be made with satisfactory flexural strength, and because these types of carbon members can be readily manufactured and processed using resin processing techniques, they are preferred.
However, carbon members formed from carbon resin composite materials have high electrical resistance compared with carbon members formed from sintered carbon. For example, if a battery is formed by stacking a carbon member formed from a carbon resin composite material and another battery member, then a problem arises in that the contract resistance between the carbon member and the other battery member is large. In particular, in those cases when the other battery member is formed from a material with a small compressive modulus such as a nonwoven fabric, felt or woven fabric, if the other battery member is laminated to the carbon member formed from a carbon resin composite material using a low surface pressure, then the contact resistance increases even further.
In those cases when a battery having a multilayer structure is formed by stacking a plurality of battery members, ensuring tight adhesion between adjacent battery members is an effective method for reducing the contact resistance between the plurality of battery members.
For example, techniques for lowering the contact resistance by integrating a plurality of battery members into a single body are disclosed in Patent Documents 1 to 4.
Further, use of an electrode material containing a gas phase method carbon fiber has been proposed as a technique for lowering the internal resistance of a battery (for example, see Patent Document 5).
Furthermore, a bipolar plate containing carbon nanotubes has been proposed as a device for improving the conductivity of a battery bipolar plate (for example, see Patent Document 6).